Sensing Torsional Vibration For Active Control

摘要

This paper demonstrates that in the area of active torsional vibration control, the standard method of measuring velocity fluctuations using a Variable Reluctance Pick-up/Toothed Gear Sensor and a demodulation circuit might be inadequate. The problem lies in the fact that the demodulation circuit includes a low pass filter that attenuates ripple caused by the carrier signal. This low pass filter produces an undesirable phase shift in the sensor signal resulting in a degradation of the control algorithm lie. Direct Velocity Feedback). Purely digital techniques using counters/DAC are prone to tooth-to-tooth spacing noise. It is demonstrated that an appropriate sensing system should have a wide separation between the carrier frequency and the excitation frequency. This results in a small phase shift while reducing ripple.